1. Field of the Invention
The present invention relates to a zoom lens, and more particularly, to a zoom lens that is compact and has high magnification with optical performance maintained or increased.
2. Description of the Related Art
Generally, a zoom lens used in a still camera or a video camera requires excellent optical performance, high magnification, and compactness. With the wide spread of electronic equipment such as portable information terminals (e.g., personal digital assistants (PDAs)) and mobile terminals, digital cameras and digital video units are increasingly being installed in such electronic equipment. As a result, the demand for increasingly compact cameras continues to grow.
A conventional compact zoom lens is disclosed in Japanese Patent Publication Nos. 1990-063007 and 1994-094996. As shown in FIGS. 1A and 1B, the conventional compact zoom lens includes a first lens group I, a second lens group II, and a third lens group III, each of which includes a plurality of lenses to compensate for aberration at a high magnification. However, since each lens group includes a plurality of lenses, there is a limitation in reducing the size of a zoom lens. In addition, since many lenses are used, the manufacturing cost is high.
Another conventional zoom lens is disclosed in Japanese Patent Publication No. 2003-322796. As shown in FIG. 2, the conventional zoom lens includes a first lens group L1, a second lens group L2, and a third lens group L3 and compensates for optical aberration using a diffraction optical element. However, since the ratio of the overall focal length at the wide-angle position to the overall optical distance of the zoom lens is great, the entire optical system is large. As a result, it is difficult to manufacture a compact zoom lens.